• 자원리싸이클링
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• 제14권3호
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• pp.48-54
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• 2005

FeCl$_3$용액으로 니켈프레임을 에칭하는 과정에서 발생한 폐액으로부터 철과 니켈을 분리, 회수하기 위해 용매추출과 환원실험을 수행했다. 추출제로 Alamine336을 사용하여 철과 니켈의 분리가 가능했으며, 유기상과 에칭폐액의 부피비가 7이상의 조건에서 99%의 철의 추출율을 얻었다. 0.01 M농도의 염산용액을 탈거액으로 사용하여 탈거액과 유기상의 부피비가 7인 조건에서 99%의 철 탈거율을 얻었다. 추출여액의 pH가 10.5이고 반응온도가 100$^{\circ}C$인 조건에서 환원제로 히드라진을 첨가하여 99%의 순도를 지닌 니켈 금속 분말을 얻었다. 용매추출과 화학환원을 이용하여 에칭폐액으로부터 니켈금속을 회수하고, 에칭액을 재생할 수도 있는 공정을 제시하였다.

• 한국결정성장학회지
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• 제13권3호
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• pp.139-144
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• 2003

유기용매로서 에탄올을 함유한 염화니켈 수용액으로부터 니켈 미분말을 제조하고 이들의 산화특성을 검토하였다. 에탄올을 함유한 염화니켈 수용액에서 히드라진의 환원반응은 반응온도에 크게 의존하였다. 히드라진에 의한 환원반응시간은 반응온도가 증가함에 따라 감소하였다. 반응온도를 제어함으로써 입경이 0.1 $\mu\textrm{m}$-1.0 $\mu\textrm{m}$ 범위를 갖는 구형 분말을 얻을 수 있었다. 또한, 반응온도가 증가함에 따라 입경은 다소 증가하였고 조대한 입자들의 존재로 인하여 넓은 입도 분포를 나타내었다. $60^{\circ}C$에서 합성된 니켈 분말의 평균 입경과 비표면적은 각각 0.3 $\mu\textrm{m}$와 31.8 $m^2$/g이었다. $300^{\circ}C$에서 니켈 분말의 중량감소는 $Ni(OH)_2$의 분해반응에 기인한 것이다. $200^{\circ}C$ 공기중에서 가열처리한 경우 내산화성은 합성 분말보다 현저하였다

• Progress in Superconductivity
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• 제7권2호
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• pp.145-151
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• 2006

Nickel and nickel-tungsten alloy were electroplated on a cold rolled and heat treated copper(Cu) substrate. 4 mm-thick high purity commercial grade Cu was rolled to various thicknesses of 50, 70, 100 and 150 micron. High reduction ratio of 30% was applied down to 150 micron. Rolled texture was converted into cube texture via high temperature heat treatment at $400-800^{\circ}C$. Grain size of Cu was about 50 micron which is much smaller compared to >300 micron for the Cu prepared using smaller reduction pass of 5%. 1.5 km-long 150 micron Cu was fabricated with a rolling speed of 33 m/min and texture of Cu was uniform along length. Abnormal grain growth and non-cube texture appeared for the specimen anneal above $900^{\circ}C$. 1-10 micron thick Ni and Ni-W film was electroplated onto an annealed cube-textured Cu or directly on a cold rolled Cu. Both specimens were annealed and the degree of texture was measured. For electroplating of Ni on annealed Cu, Ni layer duplicated the cube-texture of Cu substrate and the FWHM of in plane XRD measurement for annealed Cu layer and electroplated layer was $9.9^{\circ}\;and\;13.4^{\irc}$, respectively. But the FWHM of in plane XRD measurement of the specimen which electroplated Ni directly on cold rolled Cu was $8.6^{\circ}$, which is better texture than that of nickel electroplated on annealed Cu and it might be caused by the suppression of secondary recrystallization and abnormal grain growth of Cu at high temperature above $900^{\circ}C$ by electroplated nickel.

• 한국표면공학회지
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• 제15권1호
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• pp.1-10
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• 1982

Electroless plating is the continious formation of metallic coatings from metal ions by che-mical reduction without the use of electrical current. This is, however, more expansive than the conventional electroplating but is often used because of certain adventage. Here, general description of past research on electroless nickel plating, especially about the merits of each research was given. Part(Ⅰ) is for the conposition of solution, pretreatment and facilities of electroless nickel plating.

• 자원리싸이클링
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• 제13권3호
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• pp.27-36
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• 2004

수소화 반응용 니켈 폐촉매를 배소하여 산화니켈을 회수한 다음, 회수한 산화니켈을 산처리하고 침전법으로 Kieselguhr에 담지 된 니켈 촉매로 재생시켰다. 폐촉매의 배소 조건이 니켈산화물의 회수에 미치는 영향을 조사하였다. 니켈 폐촉매의 재생 과정에서 $1,000^{\circ}C$의 온도에서 배소 하였을 경우에 대부분 니켈산화물로 회수할 수 있었다. 산화니켈을 산처리하여 얻은 질산니켈을 사용하여 Kieselguhr에 담지 된 니켈 촉매를 제조하였다. 이때 조촉매의 첨가, 침전 조건 및 환원 조건 등이 재생된 촉매의 식물성 오일의 수소화 반응 성능에 미치는 영향을 조사하였다. 알카리 금속인 CaO와 희토류 금속인 $Ce_2$$O_3$를 조촉매로 첨가했을 때 수소화 반응의 활성이 증가하였다.

• 한국표면공학회지
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• 제56권5호
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• pp.320-327
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• 2023

In this study, the nickel hydroxide (Ni(OH)₂) electrode for supercapacitor was prepared via hydrothermal method. Based on the nickel (Ni) foam, the electrode does not require any additional binder material or post-processing. Nickel nitrate (Ni(NO₃)₂) and hexamethylenetetramine (C₆H₁₂N₄) were used for synthesis, and the synthesis condition was 12 hours at 80 ℃. X-ray diffraction (XRD) and field-emission scanning electron microscopy (FE-SEM) were used to analyze the structural characteristics of the electrode, and it shown that the nickel hydroxide was successfully prepared after only the one-step hydrothermal synthesis. The electrochemical properties were analyzed through the half-cell test. The prepared electrode shown a pair of oxidation/reduction peaks, indicating that the driving method included the redox reaction on the electrode surface. After the charge/discharge test, the specific capacitance was calculated as the value of 438 F/g at 3 A/g.

• Bulletin of the Korean Chemical Society
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• 제33권7호
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• pp.2279-2286
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• 2012

The template synthesis of copper(II) and nickel(II) complexes derived from 2,6-diformyl-4-methylphenol with diethylenetriamine or 1,2-bis(3-aminopropylamino)ethane produce the 12-membered $N_3O$ and 17-membered $N_4O$ macrocyclic complexes, respectively. The geometry of the complexes has been determined with the help of electronic and EPR spectroscopic values and found to be five coordinated square pyramidal and, six coordinated distorted tetragonal for 12-membered and 17-membered macrocyclic complexes, respectively. Electrochemical studies of the mononuclear $N_3O$ and $N_4O$ copper(II) complexes show one irreversible oneelectron reduction wave at $E_{pc}=-1.35$ and -1.15 V respectively, and the corresponding nickel(II) complexes show irreversible one-electron reduction wave at $E_{pc}=-1.25$ and -1.22 V, respectively. The nickel(II) complexes show irreversible one-electron oxidation wave at $E_{pa}=+0.84$ and +0.82 V, respectively. All the complexes were evaluated for in vitro antimicrobial activity against the human pathogenic bacteria and fungi.

• Korean Journal of Chemical Engineering
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• 제35권11호
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• pp.2321-2326
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• 2018

We evaluated the optimal conditions for fluidization of nickel oxide (NiO) and its reduction into high-purity Ni during hydrogen reduction in a laboratory-scale fluidized bed reactor. A comparative study was performed through structural shape analysis using scanning electron microscopy (SEM); variance in pressure drop, minimum fluidization velocity, terminal velocity, reduction rate, and mass loss were assessed at temperatures ranging from 400 to $600^{\circ}C$ and at 20, 40, and 60 min in reaction time. We estimated the sample weight with most active fluidization to be 200 g based on the bed diameter of the fluidized bed reactor and height of the stocked material. The optimal conditions for NiO hydrogen reduction were found to be height of sample H to the internal fluidized bed reactor diameter D was H/D=1, reaction temperature of $550^{\circ}C$, reaction time of 60 min, superficial gas velocity of 0.011 m/s, and pressure drop of 77 Pa during fluidization. We determined the best operating conditions for the NiO hydrogen reduction process based on these findings.

• 한국재료학회지
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• 제15권5호
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• pp.334-339
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• 2005

Nickel Powders were synthesized by the reduction of $Ni(OH)_2$ reactant slurries from nonaqueous media, and the morphological characteristics of nickel powders with the addition of NaOH, the composition of mixed solvents, reaction temperature and reaction time were investigated. The NaOH addition changed the structure of agglomeration in the submicron range. As the volume ratio of TEA to DEA increased, the powders slightly suppressed the agglomeration between particles and their size increased. The reaction temperature on size and shape of nickel powders was significant. As reaction time was shortened from 40 min to 0.3 min at $220^{\circ}C$, size distribution of nickel powders was transferred to a narrow size distribution owing to the presence of smaller particles with below $1.0\;{\mu}m$.

• 대한금속재료학회지
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• 제49권1호
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• pp.52-57
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• 2011

Nickel ferrite ($NiFe_2O_4$) powder was prepared through the ceramic route by calcination of a stoichiometric mixture of nickel oxide (NiO) and iron oxide ($Fe_2O_3$). The pressed pellets of $NiFe_2O_4$ were isothermally reduced in pure hydrogen at 800, 900, 1000 and $1100^{\circ}C$. Based on thermogravimetric analysis, the reduction behavior and the kinetic reaction mechanisms of the synthesized ferrite were studied. The initial ferrite powder and various reduction products were characterized by XRD, SEM, reflected light microscope and VSM to reveal the effect of hydrogen reduction on the composition, microstructure, magnetic properties and reaction kinetics of the produced Fe-Ni alloy. Complete reduction of the $NiFe_2O_4$ was achieved with synthesis of homogeneous nanocrystalline Fe-Ni alloys. Arrhenius equation with the approved mathematical formulations for a gas-solid reaction was applied for calculating the activation energy ($E_a$) values and detecting the controlling reaction mechanism.